Xa
From Resin 3.0
The <xa> directive in the <database> configuration specifies how the connections should participate in distributed transactions.
If true, connections automatically participate in any distributed transaction, i.e. a UserTransaction.begin() will enlist the connection into the new transaction and commit() will commit the transactions.
The default value is true.
Non-transactional data sources
In some cases, it is convenient to have a transactional (xa) data source and a non-transactional data source to the same database. For example, a connection that only selects data from read-only tables does not need to participate in a transaction. In that case, it is more efficient to mark the read-only connection as non-transactional by setting <xa>false</xa>